Diaminopyrazole derivatives and their use for oxidation dyeing of keratinous fibres

ABSTRACT

The invention concerns novel diaminopyrazole derivatives of formula (I), wherein: R 1  represents C 1 -C 6  alkyl or C 2 , preferably up to C 4 , alkenyl, linear or branched, bearing at least a substituent selected among OR, NHR, NRR′, SR, SO 2 R, COOH, CONH 2 , CONRR′, PO(OH) 2 , SH, SO 3 X, a non-cationic heterocycle, Cl, Br or I; X represents H, Na, K or NH 4 ; R and R′, identical or different, represent C 1 -C 6  alkyl or C 2 -C 6 , preferably up to C 4 , alkenyl, linear or branched, unsubstituted or substituted by one or several functional groups selected among OH, NH 2 , OR, NHR, NRR′, SR, SOR, SO 2 R, COOH, CONH 2 , CONRR′, PO(OH) 2 , SH, SO 3 X, a non-cationic heterocycle, Cl, Br or I, X, R and R′ having the definitions mentioned above; R 2  represents H, or C 1 -C 6  alkyl or C 2 -C 6 , preferably up to C 4 , alkenyl, linear or branched, unsubstituted or substituted by one or several functional groups selected among OH, NH 2 , OR, NHR, NRR′, SR, SOR, SO 2 R, COOH, CONH 2 , CONRR′, PO(OH) 2 , SH, SO 3 X, a non-cationic heterocycle, Cl, Br or I, X, R and R′ having the definitions mentioned above; and their physiologically acceptable salts, and their use for oxidation dyeing of keratinous fibres, in particular human hair.

[0001] The present invention relates to novel diaminopyrazolederivatives, to a composition for the oxidation dyeing of keratinfibers, and in particular of human keratin fibers such as the hair,comprising at least one diaminopyrazole derivative as oxidation base,and to the oxidation dyeing processes using it.

[0002] It is known practice to dye keratin fibers, and in particularhuman hair, with dye compositions containing oxidation dye precursors,in particular ortho- or paraphenylenediamines, ortho-aminophenols orparaminophenols and heterocyclic compounds such as diaminopyrazolederivatives, which are generally referred to as oxidation bases. Theoxidation dye precursors, or oxidation bases, are colorless or weaklycolored compounds which, when combined with oxidizing products, can giverise to colored compounds and dyes by a process of oxidativecondensation.

[0003] It is also known that the shades obtained with these oxidationbases can be varied by combining them with couplers or colorationmodifiers, the latter being chosen in particular from aromaticmeta-diamines, metaminophenols, meta-diphenols and certain heterocycliccompounds.

[0004] The variety of molecules used as oxidation bases and couplersmakes it possible to obtain a wide range of colors.

[0005] The so-called “permanent” coloration obtained by means of theseoxidation dyes must moreover satisfy a certain number of requirements.Thus, it must have no toxicological drawbacks and it must allow shadesof the desired strength to be obtained and have good resistance toexternal agents (light, bad weather, washing, permanent-waving,perspiration and friction).

[0006] The dyes must also allow white hairs to be covered, and, lastly,they must be as unselective as possible, i.e. they must allow thesmallest possible differences in coloration to be produced over theentire length of the same keratin fiber, which may indeed be differentlysensitized (i.e. damaged) between its tip and its root. They must alsoshow good chemical stability in the formulations, and must have a goodtoxicological profile.

[0007] Furthermore, for a certain number of applications, dyes thatproduce chromatic shades on the hair are desired.

[0008] Patent applications DE 42 34 885, 196 43 059 and 196 46 609disclose 4,5-diaminopyrazole derivatives, which, when used together withvarious couplers, especially benzoxazines, give chestnut-brown shadeswith blue, red, violet, aubergine or coppery glints.

[0009] However, these dyes do not satisfy all the above requirements.

[0010] The Applicant has now discovered, entirely surprisingly andunexpectedly, that it is possible to obtain dyes, which are capable ofproducing powerful, particularly chromatic, bright and relativelyunselective colorations, which have excellent properties of resistanceto the various attacking factors to which keratin fibers may besubjected, by using as oxidation base the diaminopyrazoles of theformula (I) below or physiologically acceptable salts thereof.

[0011] One subject of the present invention is thus the noveldiaminopyrazoles having the following structure:

[0012] in which

[0013] R₁ denotes a linear or branched C₁-C₆ alkyl radical or C₂-C₆ andpreferably up to C₄ alkenyl radical, bearing at least one substituentchosen from OR, NHR, NRR′, SR, SOR, SO₂R, COOH, CONH₂, CONRR′, PO(OH)₂,SH, SO₃X, a non-cationic heterocycle, Cl, Br and I,

[0014] X denotes H, Na, K or NH₄,

[0015] R and R′, which may be identical or different, denote a linear orbranched C₁-C₆ alkyl radical or C₂-C₆ and preferably up to C₄ alkenylradical, which is unsubstituted or substituted with one or morefunctional groups chosen from OH, NH₂, OR, NHR, NRR′, SR, SOR, SO₂R,COOH, CONH₂, CONRR′, PO(OH)₂, SH, SO₃X, a non-cationic heterocycle, Cl,Br and I, X, R and R′ having the meanings given above,

[0016] R₂ denotes H or a linear or branched C₁-C₆ alkyl radical or C₂-C₆and preferably up to C₄ alkenyl radical, which is unsubstituted orsubstituted with one or more functional groups chosen from OH, NH₂, OR,NHR, NRR′, SR, SOR, SO₂R, COOH, CONH₂, CONRR′, PO(OH)₂, SH, SO₃X, anon-cationic heterocycle, Cl, Br and I, X, R and R′ having thedefinitions given above.

[0017] A subject of the invention is also the salts with physiologicallyacceptable acids or bases of the compounds of formula (I), such as thehydrochlorides, hydrobromides, sulfates, tartrates, lactates oracetates, or the salts obtained with sodium hydroxide, potassiumhydroxide, ammonia, amines or alkanolamines.

[0018] A subject of the invention is also a composition for theoxidation dyeing of keratin fibers, and in particular of human keratinfibers such as the hair, characterized in that it contains, in a mediumthat is suitable for dyeing, as oxidation base, at least onediaminopyrazole of formula (I) above, or salts thereof withphysiologically acceptable acids or bases.

[0019] As mentioned above, the colorations obtained with the oxidationdye composition in accordance with the invention are powerful,particularly bright and chromatic. They in particular produce shadesthat are free of or contain very little blue or yellow. Furthermore,they show excellent properties of resistance with respect to the actionof various external agents (light, bad weather, washing,permanent-waving, perspiration and friction).

[0020] A subject of the invention is also a process for the oxidationdyeing of keratin fibers using such a dye composition.

[0021] As examples of diaminopyrazoles of formula (I) according to theinvention, mention may be made of the compounds belonging to thefollowing classes: Structure Name Structure Name Structure Name

2-(4,5- diamino- pyrazol-1- yl)ethane- sulfonic acid

2-(4,5- diamino- pyrazol-1- yl)- propane-1- sulfonic acid

1-(4,5- diamino- pyrazol-1- yl)- propane-2- sulfonic acid

3-(4,5- diamino- pyrazol-1- yl)butane- 2-sulfonic acid

3-(4,5- diamino- pyrazol-1- yl)- propane-1- sulfonic acid

3-(4,5- diamino- pyrazol-1- yl)butane- 1-sulfonic acid

3-(4,5- diamino- pyrazol-1- yl)-2- methyl- propane-1- sulfonic acid

4-(4,5- diamino- pyrazol-1- yl)butane-2- sulfonic acid

4-(4,5- diamino- pyrazol-1- yl)butane- 1-sulfonic acid

4-(4,5- diamino- pyrazol-1- yl)- pentane-1- sulfonic acid

4-(4,5- diamino- pyrazol-1- yl)-3- methyl- butane-1- sulfonic acid

4-(4,5- diamino- pyrazol-1- yl)-2- methyl- butane-1- sulfonic acid

5-(4,5- diamino- pyrazol-1- yl)- pentane-2 sulfonic acid

5-(4,5- diamino- pyrazol-1- yl)- pentane-1- sulfonic acid

5-(4,5- diamino- pyrazol-1- yl)hexane- 1-sulfonic acid

5-(4,5- diamino- pyrazol-1- yl)-4- methyl- pentane-1 sulfonic acid

5-(4,5- diamino- pyrazol-1- yl)-3- methyl- pentane-1- sulfonic acid

5-(4,5- diamino- pyrazol-1- yl)-2- methyl- pentane-1- sulfonic acid

6-(4,5- diamino- pyrazol-1- yl)hexane- 2-sulfonic acid

6-(4,5- diamino- pyrazol-1- yl)hexane-1- sulfonic acid

2-(4-amino- 5-methyl- amino- pyrazol-1- yl)ethane- sulfonic acid

2-(4- amino-5- ethyl- amino- pyrazol-1- yl)ethane- sulfonic acid

2-[4-amino- 5-(2- hydroxy- ethylamino)- pyrazol-1- yl]ethane- sulfonicacid

2-[4-amino- 5-(2-meth- oxyethyl- amino)- pyrazol-1- yl]ethane- sulfonicacid

[4-amino- 2-[2- ethyl)-2H- pyrazol-3- ylamino]- acetic acid

2-[4-amino- 5-(2-amino- ethylamino]- pyrazol-1- yl]ethane- sulfonic acid

3-(4-amino- 5-methyl- aminopyrazol- 1-yl)- propane-1- sulfonic acid

3-(4- amino-5- ethyl- amino- pyrazol-1- yl)- propane-1- sulfonic acid

3-[4-amino- 5-(2- hydroxy- ethyl- amino)- pyrazol-1- yl})- propane-1-sulfonic acid

3-[4-amino- 5-(2- methoxyethyl- amino)- pyrazol-1- yl]propane-1-sulfonic acid

[4-amino- 2-(3- sulfo- propyl)- 2H- pyrazol-3- ylamino]- acetic acid

3-[4-amino- 5-(2-amino- ethylamino)- pyrazol-1- yl]-propane- 1-sulfonicacid

2-(4,5- diamino- pyrazol-1- yl)- acetamide

2-(4,5- diamino- pyrazol-1- yl)propion- amide

3-(4,5- diamino- pyrazol-1- yl)propion- amide

3-(4,5- diamino- pyrazol-1- yl)butyr- amide

3-(4,5- diamino- pyrazol-1- yl)-2- methyl- propionamide

4-(4,5- diamino- pyrazol-1- yl)butyr- amide

4-(4,5- diamino- pyrazol-1- yl)pentan- oic acid amide

4-(4,5- diamino- pyrazol-1- yl)-3- methyl- butyramide

4-(4,5- diamino- pyrazol-1- yl)-2- methyl- butyramide

5-(4,5- diamino- pyrazol-1- yl)penta- noic acid amide

5-(4,5- diamino- pyrazol-1- yl)hexanoic acid amide

5-(4,5- diamino- pyrazol-1- yl)-4- methyl- pentanoic acid amide

5-(4,5- diamino- pyrazol-1- yl)-3- methyl- pentanoic acid amide

5-(4,5- diamino- pyrazol-1- yl)-2- methyl- pentanoic acid amide

6-(4,5- diamino- pyrazol-1- yl)hexanoic acid amide

2-(4- amino-5- methyl- amino- pyrazol-1- yl)acet- amide

2-(4-amino- 5- ethylamino- pyrazol-1- yl)acetamide

2-[4-amino 5-(2- hydroxy- ethyl- amino)pyra- zol-1- yl]acet- amide

2-[4- amino-5- (2- methoxy- ethyl- amino)- pyrazol-1- yl]- acetamide

2-[4-amino- 5-(2-amino- ethylamino)- pyrazol-1- yl]acetamide

(3-amino-2- carbamoyl- methyl-2H- pyrazol-3- ylamino)- acetic acid

3-(4- amino-5- methyl- aminopyraz- ol-1- yl)propion amide

3-(4-amino- 5-ethyl- amino- pyrazol-1- yl)propion- amide

3-[4-amino- 5-(2- hydroxy- ethyl- amino)- pyrazol-1- yl]propion- amide

3-[4- amino-5- (2- methoxy- ethylamino)- pyrazol-1- yl]propion amide

3-[4-amino 5-(2-amino- ethylamino)- pyrazol-1- yl]propion- amide

[4-amino-2- (2- carbamoyl- ethyl)-2H- pyrazol-3- ylamino]- acetic acid

(4,5- diamino- pyrazol-1- yl)acetic acid

2-(4,5- diamino-nl pyrazol-1- yl)propionic acid

3-(4,5- diamino- pyrazol-1- yl)- propionic acid

3-(4,5- diamino- pyrazol-1- yl)butyric acid

3-(4,5- diamino- pyrazol-1- yl)-2- methyl- propionic acid

4-(4,5- diamino- pyrazol-1- yl)butyric acid

4-(4,5- diamino- pyrazol-1- yl)penta- noic acid

4-(4,5- diamino- pyrazol-1- yl)-3- methyl- butyric acid

4-(4,5- diamino- pyrazol-1- yl)-2- methyl- butyric acid

5-(4,5- diamino- pyrazol-1- yl)penta- noic acid

5-(4,5- diamino- pyrazol-1- yl)hexanoic acid

5-(4,5- diamino- pyrazol-1- yl)-4- methyl- pentanoic acid

5-(4,5- diamino- pyrazol-1- yl)-3- methyl- pentanoic acid

5-(4,5- diamino- pyrazol-1- yl)-2- methyl- pentanoic acid

6-(4,5- diamino- pyrazol-1- yl)hexanoic acid

(4-amino- 5-methyl- amino- pyrazol-1- yl)acetic acid

(4-amino-5- ethylamino- pyrazol-1- yl)acetic acid

[4-amino-5- (2-hydroxy- ethyl- amino)- pyrazol-1- yl]acetic acid

[4-amino 5- (carboxy- methyl- amino)- pyrazol-1- yl]acetic acid

[4-amino-5- (2- aminoethyl- amino)- pyrazol-1- yl]acetic acid

2-(2- dimethyl- amino- ethyl)-2H- pyrazole- 3,4-diamine

2-(2- dimethyl- amino-1- methyl- ethyl)-2H- pyrazol- 3,4-diamine

2-(2- dimethyl- amino- propyl)-2H- pyrazole- 3,4-diamine

2-(2- dimethyl- amino-1- methyl- propyl)- 2H- pyrazol- 3,4- diamine

2-(3- dimethyl- amino- propyl)-2H- pyrazole- 3,4-diamine

2-(3- dimethyl- amino-1- methyl- propyl)-2H- pyrazole- 3,4-diamine

2-(3- dimethyl- amino-2- methyl- propyl)- 2H- pyrazol- 3,4- diamine

2-(3- dimethyl- aminobutyl)- 2H-pyrazole- 3,4-diamine

2-(4- dimethyl- amino- butyl)-2H- pyrazol- 3,4-diamine

2-(4- dimethyl- amino-1- methyl- butyl)-2H- pyrazol- 3,4- diamine

2-(4- dimethyl- amino-2- methyl- butyl)-2H- pyrazol- 3,4-diamine

2-(4- dimethyl- amino-3- methyl)- butyl)-2H- pyrazol- 3,4-diamine

2-(4- dimethyl- amino- pentyl)- 2H- pyrazole- 3,4- diamine

2-(5- dimethyl- amino- pentyl)-2H- pyrazole- 3,4-diamine

2-(5- dimethyl- amino-1- methyl- pentyl)-2H- pyrazole- 3,4-diamine

2-(5- dimethyl- amino-2- methyl- pentyl)- 2H- pyrazole- 3,4- diamine

2-(5- dimethyl- amino-3- methyl- pentyl)-2H- pyrazole- 3,4-diamine

2-(5- dimethyl- amino-4- methyl- pentyl)-2H- pyrazole- 3,4-diamine

2-(5- dimethyl- amino- hexyl)-2H- pyrazole- 3,4- diamine

2-(6- dimethyl- aminohexyl)- 2H-pyrazole- 3,4-diamine

2-(2- dimethyl- amino- ethyl)-N3- methyl-2H- pyrazole- 3,4-diamine

2-(2- dimethyl- amino- ethyl)-N3- ethyl-2H- pyrazole- 3,4- diamine

2-[4-amino- 2-(2- dimethyl- aminoethyl)- 2H-pyrazol- 3-ylamino]- ethanol

2-(2- dimethyl- amino- ethyl)-N3- (2-methoxy- ethyl)-2H- pyrazole-3,4-dimaine

[4-amino- 2-(2- dimethyl- amino- ethyl)-2H- pyrazol-3- ylamino]- aceticacid

N3-(2-amino- ethyl)-2-(2- dimethyl- aminoethyl)- 2H-pyrazole-3,4-diamine

2-(3- dimethyl- amino- propyl)-N3- methyl-2H- pyrazole- 3,4-diamine

2-(3- dimethyl- amino- propyl)- N3-ethyl- 2H- pyrazol- 3,4- diamine

2-[4-amino- 2-(3-di- methylamino- propyl)-2H- pyrazol-3- ylamino]-ethanol

2-(3- dimethyyl- amino- propyl)-N3- (2-methoxy- ethyl)-2H- pyrazole-3,4-diamine

[4-amino- 2-(3- dimethyl- amino- propyl)- 2H- pyrazol-3- ylamino]-acetic acid

N3-(2- aminoethyl)- 2-(3- dimethyl- propyl)-2H- pyrazole- 3,4-diamine

2-(2- methyl- amino- ethyl)-2H- pyrazole- 3,4-diamine

2-(2- ethyl- amino- ethyl)-2H- pyrazole- 3,4- diamine

2-[2-(4,5- diamino- pyrazol-1- yl)ethyl- amino]- ethanol

2-(2- pyrrolidin- 1-ylethyl)- 2H- pyrazole- 3,4-diamine

1-[2-(4,5- diamino- pyrazol-1- yl)ethyl]- pyrrol- idin-3-ol

2-(2- imidazo- lidin-1-yl- ethyl)-2H- pyrazzole- 3,4-diamine

2-(2- piperazin- 1-ylethyl)- 2H- pyrazole- 3,4-diamine

2-{4-[2- (4,5- diamino- pyrazol-1- yl)ethyl]- piperazin- 1- yl}ethanol

N3-methyl-2- (2-methyl- aminoethyl)- 2H-pyrazole- 3,4-diamine

2-(2-ethyl- amino- ethyl)-N3- methyl-2H- pyrazole- 3,4-diamine

2-[2-(4- amino-5- methyl- amino- pyrazol-1- yl)ethyl- amino]- ethanol

N3-methyl-2- (2- pyrrolidin- 1-ylethyl)- 2H-pyrazole- 3,4-diamine

1-[2-(4- amino-5- methyl- amino- pyrazol-1- yl)ethyl]- pyrrolidin- 3-ol

2-(2- imidazo- lidin-1- ylethyl)- N3-methyl- 2H- pyrazole- 3,4- diamine

N3-methyl-2- (2- piperazin-1- ylethyl)-2H- pyrazole- 3,4-diamine

2-{4-[2-(4- amino-5- methyl- amino- pyrazol-1- yl)ethyl]- piperazin- 1-yl}ethanol

2-(2- methoxy- ethyl)-2H- pyrazole- 3,4- diamine

2-(2- methoxy-1- methyl- ethyl)-2H- pyrazole- 3,4-diamine

2-(2- methoxy- propyl)-2H- pyrazole- 3,4-diamine

2-(2- methoxy-1- methyl- propyl)- 2H- pyrazole- 3,4- diamine

2-(3- methoxy- propyl)-2H- pyrazole- 3,4-diamine

2-(3- methoxy-1- methyl- propyl)-2H- pyrazole- 3,4-diamine

2-(3- methoxy-2- methyl- propyl)- 2H- pyrazole- 3,4- diamine

2-(3- methoxy- butyl-2H- pyrazole- 3,4-diamine

2-(4- methoxy- butyl)-2H- pyrazole- 3,4-diamine

2-(4- Methoxy-1- methyl- butyl)-2H- pyrazole- 3,4- diamine

2-(4-Methoxy- 2-methyl- butyl)-2H- pyrazole-3,4- dianmine

2-(4- Methoxy-3- methyl- butyl)-2H- pyrazole- 3,4-diamine

2-(4- Methoxy- pentyl)- 2H- pyrazole- 3,4- diamine

2-(5-Methoxy- pentyl)-2H- pyrazole-3,4- diamine

2-(5- Methoxy-1- methyl- pentyl)-2H- pyrazole- 3,4-diamine

2-(5- Methoxy-2- methyl- pentyl)- 2H- pyrazole- 3,4- diamine

2-(5-Methoxy- 3-methyl- pentyl)-2H- pyrazole-3,4- diamine

2-(5- Methoxy-4- methyl- pentyl)-2H- pyrazole- 3,4-diamine

2-(5- Methoxy- hexyl)-2H- pyrazole- 3,4- diamine

2-(6-Methoxy- hexyl)-2H- pyrazole-3,4- diamine

2-(2- Methoxy- ethyl)-N3- methyl-2H- pyrazole- 3,4-diamine

N3-Ethyl- 2-(2- methoxy- ethyl)-2H- pyrazole- 3,4- diamine

2-[4-Amino-2- (2-methoxy- ethyl)-2H- pyrazol-3- ylamino]- ethanol

2,N3-Bis- 2-(methoxy- ethyl)-2H- pyrazole- 3,4-diamine

[4-Amino- 2-(2- methoxy- ethyl)-2H- pyrazol-3- ylamino]- acetique acide

N3-(2-Amino- ethyl)-2-(2- methoxy- ethyl)-2H- pyrazole-3,4- diamine

2-(3- Methoxy- propyl)-N3- methyl-2H- pyrazole- 3,4-diamine

N3-ethyl- 2-(3- methoxypro- pyl)-2H- pyrazole- 3,4- diamine

2-[4-amino- 2-(3- methoxy- propyl)-2H- pyrazol-3- ylamino]- ethanol

N3-(2- methoxy- ethyl)-2- (3-methoxy- propyl)-2H- pyrazole- 3,4-diamine

[4-amino- 2-(3- methoxy- propyl)- 2H- pyrazol-3- ylamino]- acetic acid

N3-(2-amino- ethyl)-2-(3- methoxy- propyl)-2H- pyrazole- 3,4-diamine

2-(2- ethoxy- ethyl)-2H- pyrazole- 3,4-diamine

2-[2-(4,5- diamino- pyrazol-1- yl)ethoxy]ethanol

2-[2-(2- methoxy- ethoxy)- ethyl]-2H- pyrazole- 3,4-diamine

2-[2-(2- amino- ethoxy)- ethyl]-2H- pyrazole- 3,4-diamine

2-[2-(4,5- diamino- pyrazole- 3,4- diamine

2-(tetra- hydrofuran- 2-ylmethyl)- 2H-pyrazole- 3,4-diamine

2-(tetra- hydropyran- 2- ylmethyl)- 2H- pyrazole- 3,4-diamine

2-(2- ethoxy- ethyl)-N3- methyl-2H- pyrazole- 3,4- diamine

2-[2-(4- amino-5- methylamino- pyrazol-1- yl)ethoxy]ethanol

2-[2-(2- methoxy- ethoxy)- ethyl]-N3- methyl-2H- pyrazole- 3,4-diamine

2-[2-(2- amino- ethoxy)- ethyl]-N3- methyl-2H- pyrazole- 3,4- diamine

2-[2-(2- dimethyl- amino- ethoxy)- ethyl]-N3- methyl-2H- pyrazole-3,4-diamine

N-3methyl- 2-(tetra- hydrofuran- 2- ylmethyl)- 2H- pyrazole- 3,4-diamine

N3-methyl- 2-(tetra- hydro pyran-2- ylmethyl)- 2H- pyrazole- 3,4-diamine

[0022] According to one preferred embodiment of the invention in formula(I), R₁ is a linear C₁-C₃ alkyl radical substituted with an SO₃H, COOH,CONH₂, methoxy, 25 hydroxyethyloxy, 2-hydroxyethylamino, mono- ordimethylamino, 1-pyrrolidinyl-3-ol, 1-imidazolidinyl, 1-piperazinyl,1-piperazinylethanol, 2-tetrahydrofuryl or 2-tetrahydropyranyl group andR₂ denotes H, methyl, ethyl, 2-hydroxyethyl, 2-methoxyethyl,2-aminoethyl or carboxymethyl.

[0023] The diaminopyrazoles of formula (I) that are preferred accordingto the invention have the following structures: Structure Name StructureName Structure Name

2-(4,5- diamino- pyrazol- 1-yl)- ethane- sulfonic acid

3-(4,5- diamino- pyrazol- 1-yl)- propion- amide

(4,5- diamino- pyrazol- 1-yl)- acetic acid

2-(2- dimethyl- amino- ethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine

2-(2- methoxy- ethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine

2-(2- methoxy- ethyl)- 2H- pyrazole- 3,4- diamine

2-(2- dimethyl- amino- ethyl)- 2H- pyrazole- 3,4- diamine

3-(4,5- diamino- pyrazol- 1-yl)pro- pane-1- sulfonic acid

2-(4- amino-5- methyl- amino- pyrazol- 1-yl)- ethane- sulfonic acid

2-[4- amino-5- (2- hydroxy- ethyl- amino)- pyrazol- 1-yl)- ethane-sulfonic acid

2-[4- amino-5- (2- methoxy- ethyl- amino)- pyrazol- 1-yl]- ethane-sulfonic acid

[4-amino- 2-(3- sulfo- propyl)- 2H- pyrazol- 3-yl- amino]- acetic acid

2-(4,5- diamino- pyrazol- 1-yl)- acetamide

4-(4,5- diamino- pyrazol- 1-yl)- butyr- amide

2-(4- amino-5- methyl- amino- pyrazol- 1- yl)acet- amide

2-[4- amino-5- (2- hydroxy- ethyl- amino)- pyrazol- 1-yl]- acetamide

(4-amino- 2-carba- moyl- methyl- 2H- pyrazol- 2- ylamino)- acetic acid

3-[4- amino-5- (2-amino- ethyl- amino)- pyrazol- 1-yl]- propion- amide

(4,5- diamino- pyrazol- 1-yl)- acetic acid

3-(4,5-diamino- pyrazol- 1-yl)- propionic acid

(4-amino- 5-methyl- amino- pyrazol- 1-yl)- acetic acid

[4-amino- 5-(2- hydroxy- ethyl- amino)- pyrazol- 1-yl]- acetic acid

[4-amino- 5- (carboxy- methyl- amino)- pyrazol- 1-yl]- acetic acid

[4-amino- 5-(2- amino- ethyl- amino)- pyrazol- 1-yl]- acetic acid

2-(2- dimethyl- amino- ethyl)- 2H- pyrazole- 3,4- diamine

2-(3- dimethyl- amino- propyl)- 2H- pyrazole- 3,4- diamine

2-(3- dimethyl- amino- propyl)- N3- methyl- 2H- pyrazole- 3,4- diamine

2-[4- amino-2- (2- dimethyl- amino- ethyl)- 2H- pyrazol- 3- ylamino]-ethanol

[4-amino- 2-(2- dimethyl- amino- ethyl)- 2H- pyrazol- 3- ylamino]-acetic acid

2-(3- dimethyl- amino- propyl)- N3-ethyl- 2H- pyrazole- 3,4- diamine

N3-(2- amino- ethyl)-2- (3- dimethyl- amino- propyl)- 2H- pyrazole- 3,4-diamine

2-(2- methyl- amino- ethyl)- 2H- pyrazole- 3,4- diamine

2-[2- (4,5- diamino- pyrazol- 1-yl)- ethyl- amino]- ethanol

1-[2- (4,5- diamino- pyrazol- 1-yl)- ethyl]- pyrroli- din-3-ol

2-(2- imidazol- idin-1- ylethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine

N3- methyl-2- (2- pipera- zin-1-yl- ethyl)- 2H- pyrazole- 3,4- diamine

2-{4-[2- (4-amino- 5-methyl- amino- pyrazol- 1-yl)- ethyl]- piper-azin-1- yl}- ethanol

2-(3- methoxy- propyl)- 2H- pyrazole- 3,4- diamine

2-(2- methoxy- ethyl)- N3- methyl- 2H- pyrazole- 3,4- diamine

2-[4- amino-2- (2- methoxy- ethyl)- 2H- pyrazol- 3- ylamino]- ethanol

[4-amino- 2-(2- methoxy- ethyl)- 2H- pyrazol- 3- ylamino]- acetic acid

N3-(2- methoxy- ethyl)-2- (3- methoxy- propyl)- 2H- pyrazole- 3,4-diamine

N3-(2- amino- ethyl)-2- (3- methoxy- propyl)- 2H- pyrazole- 3,4- diamine

2-[2- (4,5- diamino- pyrazol- 1-yl)- ethoxy]- ethanol

2-[2-(2- methoxy- ethoxy)- ethyl]- 2H- pyrazole- 3,4- diamine

2-[2-(2- amino- ethoxy)- ethyl]- 2H- pyrazole- 3,4- diamine

2-[2-(2- dimethyl- amino- ethoxy)- ethyl]- 2H- pyrazole- 3,4- diamine

N3- methyl-2- (tetra- hydro- furan-2- yl- methyl)- 2H- pyrazole- 3,4-diamine

N3- methyl-2- (tetra- hydro- pyran-2- yl- methyl)- 2H- pyrazole- 3,4-diamine

[0024] The diaminopyrazoles of formula (I) that are more particularlypreferred according to the invention are4,5-diamino-1-(2′-methoxyethyl)pyrazole and4-amino-1-(2′-methoxyethyl)-5-methylaminopyrazole, or the addition saltsthereof with physiologically acceptable acids.

[0025] The diaminopyrazoles of formula (I) according to the inventionare prepared, for example, according to the following generalpreparation method:

[0026] The synthetic approach shown below is described in the literatureup to intermediate (2) (J. H. P. Juffermanns, C. L.; Habraken; J. Org.Chem., 1986, 51, 4656; Klebe et al., Synthesis, 1973, 294; R. Hüttel, F.Büchele; Chem. Ber., 1955, 88, 1586).

[0027] The alkylation and the amination to obtain the compounds of thetype (5) of formula (I) according to the invention are mentioned indocument DE 42 34 885.

[0028] Examples of Synthesis:

[0029] Synthesis of 3,4,5-tribromopyrazole (1):

[0030] NaOH (24 g, 0.6 mol) was added to an aqueous solution of pyrazole(10 g, 0.147 mol) with stirring (the temperature of the reaction mediumis raised to 35° C.). After cooling the reaction medium to 20° C., Br₂(72 g, 0.45 mol) was added dropwise over 1 hour, while maintaining thetemperature between 20° C. and 25° C. The reaction was monitored by TLC(thin layer chromatography) (50% hexane/50% EtOAc or ethyl acetate). Theprecipitate was filtered off and washed with demineralized water (100ml). The filtrate was acidified to pH 6-7 using HCl (10%, 33 g, 0.27mol) and maintaining the temperature between 20 and 25° C. Theprecipitate thus formed was filtered off and washed with demineralizedwater (100 ml). The combined solids were maintained at reflux inDean-Stark apparatus in the presence of toluene (200 ml). At the end ofcollection of the water, the organic phase was filtered while hot. Thesolvent was evaporated down to a residual volume of 110 ml. The solutionwas cooled to 0-5° C. for 1 hour. The precipitate formed was collectedby filtration, washed with cold toluene (20 ml) and dried under vacuumat 80° C. to give the tribromide (1) in the form of an off-white solid(30 g, 67%). NMR: ¹³C (100 MHz, d₆-DMSO): 97.7, 116.1, 126.4 IR (KBr;cm⁻¹): 3100, 2861, 1531, 1356, 1019, 969 m.p.: 182-184° C.

[0031] Synthesis of 3,5-dibromo-4-nitropyrazole (2):

[0032] HNO₃ (d=1.50 g/ml; 18 ml, 0.429 mol) was added dropwise over 10minutes to a solution of 3,4,5-tribromopyrazole (50 g, 0.164 mol) inglacial acetic acid (750 ml) while maintaining the temperature at 15° C.Acetic anhydride (250 ml) was added and the reaction mixture was stirredat room temperature for 2 hours. Once the reaction was complete, thereaction mixture was poured onto crushed ice (1 kg). After stirring for1 hour, the crude product was filtered off and then washed withdemineralized water (2×60 ml) to give crude1-nitro-3,4,5-tribromopyrazole. The water (24.6 ml) contained in the wetproduct was removed by heating a solution of the product in toluene (750ml) at reflux in Dean-Stark apparatus. The toluene solution wasmaintained at reflux for a further 30 minutes until a TLC (eluent:toluene) showed that the rearrangement of the1-nitro-3,4,5-tribromopyrazole (Rf=0.77), the intermediate formed, into3,4,5-dibromo-4-nitropyrazole 2 (Rf=0.05) was complete. The solution wasconcentrated to a residual volume of 150 ml and then allowed to cool to60° C., followed by addition of hexane (275 ml). The solution was cooledto 0-5° C. for 1 hour and the 3,5-dibromo-4-nitropyrazole 2 (29.1 g,65%) was recovered by filtration and drying under vacuum in the form ofa pale yellow solid. IR (KBr, cm⁻¹): 3211, 1541, 1441, 1370, 1334, 976,960, 824 m.p.: 127.6-130.1° C.

[0033] General Method for Synthesizing the1-alkyl-3,5-dibromo-4-nitropyrazole (3):

[0034] A solution of 3,5-dibromo-4-nitropyrazole (2) (1 mmol) in DMF(dimethylformamide) (4.8 ml) was added dropwise to a solution of NaH(1.1 mmol; 60% dispersion in oil, prewashed with hexane under an inertatmosphere) in DMF (8 ml) with stirring. An evolution of hydrogen gastook place. After 30 minutes, a solution of alkyl halide (1.2 mmol) inDMF (1.6 ml) was added dropwise over 10 minutes, followed by heating thereaction medium to 50-60° C. for 3 hours (monitored by TLC). The DMF wasevaporated off under reduced pressure and the residue was taken up in amixture of DCM (dichloromethane) (4 ml) and water (10 ml). The aqueousphase was extracted with DCM (3×10 ml) and the combined organic phaseswere washed with water (50 ml). The organic phase was dried over MgSO₄and the solvent was evaporated off under reduced pressure to give thealkylated products of the type (3) in the form of oils or solids. Theproducts were used without further purification in the amination step.

[0035] General Method for Synthesizing the1-alkyl-5-alkylamino-3-bromo-4-nitropyrazole (4):

[0036] A mixture of 1-alkyl-3,5-dibromo-4-nitropyrazole (1 mmol) andalkylamine (14 mmol) in ethanol (25 ml) was refluxed for 4 hours(monitored by TLC). The ethanol and the excess alkylamine wereevaporated off under reduced pressure. After trituration of the crudereaction mixtures with isopropyl ether, the compounds of the type (4)were obtained as solids.

[0037] Synthesis of3-bromo-1-(2′-methoxyethyl)-5-methylamino4-nitropyrazole (compound ofthe type 4):

[0038] Aqueous 40% methylamine solution (300 ml, 8.71 mol) was added toa solution of 3,5-dibromo-1-(2′-methoxyethyl)₄-nitropyrazole (15 g,0.483 mol) in ethanol (300 ml). The reaction mixture was stirred at20-25° C. for 2 hours and then cooled to 0-5° C. for 30 minutes. Theprecipitate formed was filtered off and washed with a cold mixture ofwater/ethanol (1/1, 30 ml). The final amine product was obtained in theform of a yellow solid (4.6 g, 36%) after drying under reduced pressure.TLC (1/1: hexane/ethyl acetate): R_(f) = 0.31 m.p.: 154.4-156.8° C. IR(KBr, cm⁻¹): 3336, 1625, 1541, 1473, 1446, 1338, 1239, 1049, 839 NMR: ¹H(400MHz, d₆-DMSO): 4.27(2H, t, J=5.0Hz, CH₂N), 3.74(2H, t, J=5.0Hz,CH₂O), 3.34(3H, s, OCH₃), 3.24(3H, d, J=5.5Hz, CH₃N).

[0039] Synthesis of3-bromo-1-(2′-methoxyethyl)-5-benzylamino-4-nitropyrazole (compound ofthe type 4):

[0040] The general method was applied using benzylamine. The final amineproduct was recrystallized in an MeOH/H₂O mixture (1/1) and was isolatedin the form of a yellow solid (48%). TLC (1/1: hexane/ethyl acetate):R_(f) = 0.46 m.p.: 91.1-93.8° C. IR (KBr, cm⁻¹): 3333, 1602, 1583, 1536,1469, 1410, 1332, 1296, 1229, 1106, 1060, 732 NMR: ¹H (400MHz, CDCl₃):7.34(5H, m, H_(arom)), 4.77(2H, d, J=6.5Hz, NHCH₂ ),4.11(2H, t, J=5.0Hz,CH₂N), 3.71(2H, t, J=5.0Hz, CH₂O), 3.34(3H, s, OCH₃).

[0041] 4-Amino-1-(2′-methoxyethyl)-5-methylaminopyrazole dichlorohydrate(compound of the type 5) or (I):

[0042] A mixture of 3-bromo-1-(2′-methoxyethyl)-5-methylamino-4-pyrazole(5 g, 18 mmol) in ethanol (500 ml) containing 10% Pd/C catalyst(Johnson-Mattey Type 487, 0.5 g dry weight) and 36% hydrochloric acid(4.1 g, 40.4 mmol) was hydrogenated in a Parr autoclave (1 l) at 1.1 MPafor 3 hours (monitored by TLC). The catalyst was removed by filtrationand washed with ethanol, and the filtrate was evaporated under reducedpressure. Under an inert atmosphere, the crude oil was taken up inethanol (80 ml) and heated to 50° C. EtOAc (80 ml) was added and themixture was maintained at room temperature for 3 hours and then cooledto 0-5° C. for 2 hours. The precipitate was recovered by filtration,washed with a cold mixture of EtOH/EtOAc (1/1, 2×30 ml) and dried undervacuum to give the final diamine dihydrochloride in the form of anoff-white solid (4.1 g, 93%). Structure Name

2-(2-Methoxyethyl)- N3-methyl-2H- pyrazole-3,4- diamine HPLC (purity):99.5% TLC (MeOH): R_(f) = 0.57 (colorless spot turning red on contactwith oxygen) m.p.: 157.6-159.8° C. IR (KBr, cm⁻¹): 3237, 3128, 2760,2546, 1621, 1112 NMR: ¹H (400 MHz, d₆-DMSO): 7.46 (1H, s, NH_(arom)),4.10, (2H,m t, J = 5.5 Hz, CH₂N), 3.62 (2H, t, J = 5.5 Hz, CH₂O), 3.22(3H, s, OCH₃), 2.84 (3H, s, NCH₃).

[0043] 4,5-Diamino-1-(2′-methoxyethyl)pyrazole dihydrochloride (compoundof the type 5) or (I):

[0044] A mixture of5-benzylamino-3-bromo-1-(2′-methoxyethyl)-4-nitropyrazole (4 g, 2.8mmol) in ethanol (500 ml) containing 10% Pd/C catalyst (Johnson-Matteytype 487, 0.5 g dry weight) and 36% hydrochloric acid (0.57 g, 5.6 mmol)was hydrogenated in a Parr autoclave (1 l) at 1 MPa for 1 hour(monitored by TLC). The catalyst was removed by filtration and washedwith ethanol, and the filtrate was evaporated under reduced pressure. Acrude orange solid was obtained (2.8 g, 108%), which was triturated inEtOAc (20 ml) for 1 hour. The solid was filtered off and washed withcold EtOAc (20 ml) and then dried under vacuum to give the diamine (type5) in the form of a beige-colored solid (0.7 g, 27%). Structure Name

2-(2-Methoxyethyl)- 2H-pyrazole-3,4- diamine HPLC (purity): 99.5% TLC(MeOH): R_(f) = 0.48 (colorless spot turning red on contact with oxygen)m.p.: 168.1-173.0° C. IR (KBr, cm⁻): 3309, 3158, 3050, 2892, 1647, 1619,1587, 1504, 1422, 1344, 1281, 1111 NMR: ¹H (400 MHz, d₆-DMSO): 7.34 (1H,s, NH_(arom)), 5.18 (1H, s_(large), NH), 4.09 (2H, t, J = 5.5 Hz, CH₂N),3.61 (2H, t, J = 5.5 Hz, CH₂O), 3.23 (3H, s, OCH₃).

[0045] The dye composition according to the invention especiallycontains from 0.001% to 10% by weight, preferably from 0.05% to 6% byweight and even more preferably from 0.1% to 3% by weight of at leastone diaminopyrazole of formula (I) or salts thereof.

[0046] The dye composition in accordance with the invention may alsocontain, in addition to the diaminopyrazole(s) defined above, at leastone additional oxidation base that may be chosen from the oxidationbases conventionally used in oxidation dyeing and among which mentionmay be made especially of paraphenylenediamines,bis(phenyl)alkylenediamines, paraminophenols, ortho-aminophenols andheterocyclic bases other than the 4,5-diaminopyrazole used in accordancewith the invention.

[0047] Among the para-phenylenediamines that may be mentioned moreparticularly, for example, are paraphenylenediamine,para-tolylenediamine, 2,6-dimethylpara-phenylenediamine,2-β-hydroxyethyl-para-phenylenediamine,2-n-propyl-para-phenylenediamine, 2-isopropylpara-phenylenediamine,N-(β-hydroxypropyl)-paraphenylenediamine, N,N-bis(β-hydroxyethyl)-paraphenylenediamine, 4-amino-N-(β-methoxyethyl)anilineand the para-phenylenediamines described in French patent application FR2 630 438, and the addition salts thereof.

[0048] Among the bis-phenylalkylenediamines that may be mentioned moreparticularly, for example, areN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(P-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylaminophenyl)tetramethylenediamine andN,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine, andthe addition salts thereof.

[0049] Among the para-aminophenols that may be mentioned moreparticularly, for example, are para-aminophenol, 4-amino-3-methylphenol,4-amino-3-fluorophenol, 4-amino-3-hydroxymethylphenol,4-amino-2-methylphenol, 4-amino-2-hydroxymethylphenol,4-amino-2-methoxymethylphenol, 4-amino-2-aminomethylphenol and4-amino-2-(β-hydroxyethylaminomethyl)phenol, and the addition saltsthereof.

[0050] Among the ortho-aminophenols that may be mentioned moreparticularly, for example, are 2-aminophenol, 2-amino-5-methylphenol,2-amino-6-methylphenol and 5-acetamido-2-aminophenol, and the additionsalts thereof.

[0051] Among the heterocyclic bases that may be mentioned moreparticularly, for example, are pyridine derivatives, pyrimidinederivatives, pyrazole derivatives other than the diaminopyrazoles offormula (I) used in accordance with the invention, and the additionsalts thereof.

[0052] When they are used, these additional oxidation bases preferablyrepresent from 0.0005% to 12% by weight relative to the total weight ofthe dye composition and even more preferably from 0.005% to 6% by weightrelative this weight.

[0053] The oxidation dye compositions in accordance with the inventionmay also contain at least one coupler and/or at least one direct dye,especially to modify the shades or to enrich them with glints.

[0054] The couplers that may be used in the oxidation dye compositionsin accordance with the invention may be chosen from the couplersconventionally used in oxidation dyeing, and among which mention may bemade especially of meta-phenylenediamines, metaminophenols,meta-diphenols, mono- or polyhydroxylated naphthalene derivatives andheterocyclic couplers such as, for example, indole or pyridinederivatives, and the addition salts thereof.

[0055] These couplers are chosen more particularly from2-methyl-5-aminophenol, 5-N-(β-hydroxyethyl)amino-2-methylphenol,6-chloro-2-methyl-5-aminophenol, 3-aminophenol, 1,3-dihydroxybenzene,1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene,2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline,3-ureido-1-dimethylaminobenzene, sesamol,1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine,6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine,1-N-(β-hydroxyethyl)amino-3,4-methylenedioxybenzene and2,6-bis(β-hydroxyethylamino)toluene, and the addition salts thereof.

[0056] When they are present, these couplers especially represent from0.0001% to 10% of the total weight of the dye composition, preferablyfrom 0.005% to 5% by weight and even more preferably from 0.1% to 3% ofthis weight.

[0057] In general, the addition salts with an acid that may be used inthe context of the dye compositions of the invention (oxidation basesand couplers) are chosen especially from the hydrochlorides,hydrobromides, sulfates, tartrates, lactates and acetates. The additionsalts with a base are especially those obtained with sodium hydroxide,potassium hydroxide, ammonia, amines or alkanolamines.

[0058] The medium that is suitable for dyeing (or support) usedaccording to the invention consists of water or of a mixture of waterand at least one organic solvent chosen from C₁-C₄ lower alkanols,polyols and polyol ethers, aromatic alcohols, similar products andmixtures thereof.

[0059] The dye composition according to the invention may also containvarious adjuvants conventionally used in compositions for dyeing thehair, such as anionic, cationic, nonionic, amphoteric or zwitterionicsurfactants or mixtures thereof, anionic, cationic, nonionic, amphotericor zwitterionic polymers or mixtures thereof, mineral or organicthickeners, antioxidants, reducing agents, sunscreens, penetratingagents, sequestering agents, fragrances, buffers, dispersants,conditioners, for instance silicones, film-forming agents, preservingagents and opacifiers.

[0060] The pH of the dye composition according to the invention isbetween 3 and 12.

[0061] Needless to say, a person skilled in the art will take care toselect this or these optional additional compound(s) such that theadvantageous properties intrinsically associated with the oxidation dyecomposition in accordance with the invention are not, or are notsubstantially, adversely affected by the envisaged addition(s).

[0062] The dye composition according to the invention may be in variousforms, such as in the form of liquids, creams or gels, or in any otherform that is suitable for dyeing keratin fibers, and especially humanhair.

[0063] Another subject of the invention is a process for dyeing keratinfibers, and in particular human keratin fibers such as the hair, usingthe dye composition as defined above.

[0064] According to this process, at least one dye composition asdefined above is applied to the fibers, for a time that is sufficient todevelop the desired coloration, either in air or using an oxidizingagent. The dye composition may optionally contain oxidation catalysts,so as to accelerate the oxidation process.

[0065] According to a first embodiment of the process of the invention,the coloration of the fibers may be performed without adding anoxidizing agent, solely by contact with atmospheric oxygen.

[0066] According to a second embodiment of the process of the invention,at least one dye composition as defined above is applied to the fibers,the color being revealed at acidic, neutral or alkaline pH using anoxidizing agent that is added to the composition just at the time ofuse, or which is present in an oxidizing composition appliedsimultaneously or sequentially in a separate manner.

[0067] According to this second embodiment of the dyeing process of theinvention, the dye composition described above is preferably mixed, atthe time of use, with an oxidizing composition containing, in a mediumthat is suitable for dyeing, at least one oxidizing agent present in anamount that is sufficient to develop a coloration. The mixture obtainedis than applied to the keratin fibers and is left for an action time of3 to 50 minutes and preferably 5 to 30 minutes, after which the fibersare rinsed, washed with shampoo, rinsed again and dried.

[0068] The oxidizing agent present in the oxidizing composition asdefined above may be chosen from the oxidizing agents conventionallyused for the oxidation dyeing of keratin fibers, and among which mentionmay be made of hydrogen peroxide, urea peroxide, alkali metal bromatesand persalts such as perborates and persulfates. Hydrogen peroxide isparticularly preferred.

[0069] The pH of the oxidizing composition containing the oxidizingagent as defined above is such that, after mixing with the dyecomposition, the pH of the resulting composition applied to the keratinfibers preferably ranges between 3 and 12, and even more preferablybetween 5 and 11. It is adjusted to the desired value by means ofacidifying or basifying agents usually used in the dyeing of keratinfibers, and as defined above.

[0070] The oxidizing composition as defined above may also containvarious adjuvants conventionally used in compositions for dyeing thehair and as defined above.

[0071] The composition that is finally applied to the keratin fibers maybe in various forms, such as in the form of liquids, creams or gels, orin any other form that is suitable for dyeing keratin fibers, andespecially human hair.

[0072] Another subject of the invention is a multi-compartment device ordyeing “kit” or any other multi-compartment packaging system, a firstcompartment of which contains the dye composition as defined above, anda second compartment of which contains the oxidizing composition asdefined above. These devices may be equipped with a means for applyingthe desired mixture to the hair, such as the devices described in patentFR-2 586 913 in the name of the Applicant.

[0073] The examples that follow are intended to illustrate theinvention.

EXAMPLES 1 TO 4 Dyeing in Alkaline Medium

[0074] The dye formulations below are prepared: 4,5-diaminopyrazole 5 ×10⁻³ mol coupler 5 × 10⁻³ mol oleyl alcohol polyglycerolated with 4.0 g2 mol of glycerol oleyl alcohol polyglycerolated with 5.7 g A.M. 4 molof glycerol, containing 78% active material (A.M.) oleic acid 3.0 goleylamine containing 2 mol of ethylene 7.0 g oxide, sold under thetrade name Ethomeen O12 by the company Akzo diethylaminopropyllaurylamino succinamate, 3.0 g A.M. sodium salt, at 55% A.M. oleylalcohol 5.0 g oleic acid diethanolamide 12.0 g propylene glycol 3.5 gethyl alcohol 7.0 g dipropylene glycol 0.5 g propylene glycol monomethylether 9.0 g sodium metabisulfite as an aqueous 0.455 g A.M. solutioncontaining 35% A.M. ammonium acetate 0.8 g antioxidant, sequesteringagent qs fragrance, preserving agent qs aqueous ammonia containing 20%NH₃ 100 g

[0075] DYEING AT ALKALINE pH Example Base Coupler 1 4,5-diamino-1-(2-6-chloro-2-methyl-5- methoxyethyl) pyrazole aminophenol dihydrochloride2 4,5-diamino-1-(2′- 2,4-diamino-1-(β- methoxyethyl) pyrazolehydroxyethyloxy)- dihydrochloride benzene dihydrochloride 34-amino-1-(2′-methoxyethyl)- 6-chloro-2-methyl-5- 5-methylaminopyrazoleaminophenol dihydrochloride 4 4-amino-1-(2′-methoxyethyl)-2,4-diamino-1-(β- 5-methylaminopyrazole hydroxyethyloxy)-dihydrochloride benzene dihydrochloride

[0076] At the time of use, each dye composition is mixed, weight forweight, with a 20-volumes aqueous hydrogen peroxide solution (6% byweight), the pH of which has been adjusted to about 2.5 withorthophosphoric acid.

[0077] The mixture is applied to natural or permanent-waved grey haircontaining 90% white hairs, at a rate of 5 g per 0.5 g of hair, for 30minutes.

[0078] The hair is then rinsed, washed with a standard shampoo anddried.

[0079] The color of the locks was evaluated in the L*a*b* system, onwhite and permanent-waved hair, using a Minolta CM 2002spectrophotometer.

[0080] In the L*a*b* space, the lightness is indicated by the value L*on a scale from 0 to 100, while the shade and the saturation areexpressed by a* and b*: a* and b* indicate two color axes, a* thered-green axis and b* the yellow-blue axis.

[0081] According to this system, the higher the value of L, the palerand less intense the color. Conversely, the lower the value of L, thedarker or more intense the color. Natural white hair Permanent-wavedwhite hair Example L* a* b* L* a* b* Example 1 39.47 30.8 16.2 33.6232.8 17.29 Example 2 25.86 23.5 0.93 19.29 19.0 1.35 Example 3 36.4328.3 1.48 29.32 30.3 1.98 Example 4 25.75 14.8 −8.36 19.53 13.2 −8.02

[0082] The 4,5-diaminopyrazoles according to the invention thus make itpossible to obtain strong and chromatic shades at alkaline pH.

EXAMPLES 5 AND 6 Dyeing in Neutral Medium

[0083] The same formulations as above are prepared, replacing theaqueous ammonia with citric acid in an amount such that the pH is equalto 7. DYEING AT NEUTRAL pH Example Base Coupler 54,5-diamino-1-(2′-methoxyethyl) 2-methyl-5- pyrazole dihydrochlorideaminophenol 6 4,5-diamino-1-(2′-methoxyethyl) 2-methyl-5- pyrazoledihydrochloride aminophenol

[0084] Locks of natural and permanent-waved grey hair containing 90%white hairs are dyed with the dye compositions 5 and 6 above in the samemanner as for the dyeing at alkaline pH.

[0085] The following shades are obtained: Natural white hairPermanent-waved white hair Example L a* b* L* a* b* Example 5 43.29 17.418.0 35.02 26.8 23.56 Example 6 42.43 18.6 8.61 32.91 27.2 9.82

[0086] At neutral pH, the 4,5-diaminopyrazoles according to theinvention make it possible to obtain strong shades.

1. A diaminopyrazole derivative of formula:

in which R₁ denotes a linear or branched C₁-C₆ alkyl radical or C₂-C₆and preferably up to C₄ alkenyl radical, bearing at least onesubstituent chosen from OR, NHR, NRR′, SR, SOR, SO₂R, COOH, CONH₂,CONRR′, PO(OH)₂, SH, SO₃X, a non-cationic heterocycle, Cl, Br and I, Xdenotes H, Na, K or NH₄, R and R′, which may be identical or different,denote a linear or branched C₁-C₆ alkyl radical or C₂-C₆ and preferablyup to C₄ alkenyl radical, which is unsubstituted or substituted with oneor more functional groups chosen from OH, NH₂, OR, NHR, NRR′, SR, SOR,SO₂R, COOH, CONH₂, CONRR′, PO(OH)₂, SH, SO₃X, a non-cationicheterocycle, Cl, Br and I, X, R and R′ having the meanings given above,R₂ denotes H or a linear or branched C₁-C₆ alkyl radical or C₂-C₆ andpreferably up to C₄ alkenyl radical, which is unsubstituted orsubstituted with one or more functional groups chosen from OH, NH₂, OR,NHR, NRR′, SR, SOR, SO₂R, COOH, CONH₂, CONRR′, PO(OH)₂, SH, SO₃X, anon-cationic heterocycle, Cl, Br and I, X, R and R′ having thedefinitions given above, and the physiologically acceptable saltsthereof.
 2. The compound of formula (I) as claimed in claim 1,characterized in that the physiologically acceptable salts are acidsalts chosen from the hydrochlorides, hydrobromides, sulfates,tartrates, lactates and acetates, or salts of bases chosen from sodiumhydroxide, potassium hydroxide, ammonia, amines and alkanolamines. 3.The compound of formula (I) as claimed in claim 1 or 2, characterized inthat R, is a linear C₁-C₃ alkyl radical substituted with a SO₃H, COOH,CONH₂, methoxy, 2-hydroxyethyloxy, 2-hydroxyethylamino, mono- ordimethylamino, 1-pyrrolidinyl-3-ol, 1-imidazolidinyl, 1-piperazinyl,1-piperazinylethanol, 2-tetrahydrofuryl or 2-tetrahydropyranyl group andR₂ denotes H, methyl, ethyl, 2-hydroxyethyl, 2-methoxyethyl,2-aminoethyl or carboxymethyl.
 4. The compound of formula (I) as claimedin any one of claims 1 to 3, characterized in that it is4,5-diamino-1-(2′-methoxyethyl)pyrazole or4-amino-1-(2′-methoxyethyl)-5-methylaminopyrazole, or a salt thereofwith physiologically acceptable acids.
 5. A composition for theoxidation dyeing of keratin fibers, and in particular of human keratinfibers such as the hair, characterized in'that it contains, in a mediumthat is suitable for dyeing, as oxidation base, at least one4,5-diaminopyrazole of formula (I):

in which R₁ denotes a linear or branched C₁-C₆ alkyl radical or C₂-C₆and preferably up to C₄ alkenyl radical, bearing at least onesubstituent chosen from OR, NHR, NRR′, SR, SOR, SO₂R, COOH, CONH₂,CONRR′, PO(OH)₂, SH, SO₃X, a non-cationic heterocycle, Cl, Br and I, Xdenotes H, Na, K or NH₄, R and R′, which may be identical or different,denote a linear or branched C₁-C₆ alkyl radical or C₂-C₆ and preferablyup to C₄ alkenyl radical, which is unsubstituted or substituted with oneor more functional groups chosen from OH, NH₂, OR, NHR, NRR′, SR, SOR,SO₂R, COOH, CONH₂, CONRR′, PO(OH)₂, SH, SO₃X, a non-cationicheterocycle, Cl, Br and I, X, R and R′ having the meanings given above,R₂ denotes H or a linear or branched C₁-C₆ alkyl radical or C₂-C₆ andpreferably up to C₄ alkenyl radical, which is unsubstituted orsubstituted with one or more functional groups chosen from OH, NH₂, OR,NHR, NRR′, SR, SOR, SO₂R, COOH, CONH₂, CONRR′, PO(OH) 2, SH, SO₃X, anon-cationic heterocycle, Cl, Br and I, X, R and R′ having thedefinitions given above, or an addition salt thereof with aphysiologically acceptable acid or base.
 6. The composition as claimedin claim 5, characterized in that it contains from 0.001% to 10% byweight of at least one diaminopyrazole of formula (I) or salt thereof.7. The composition as claimed in claim 6, characterized in that itcontains from 0.05% to 6% by weight and preferably 0.1% to 3% by weightof at least one diaminopyrazole of formula (I) or salts thereof.
 8. Thecomposition as claimed in any one of claims 5 to 7, characterized inthat the medium that is suitable for dyeing (or support) consists ofwater or of a mixture of water and at least one organic solvent chosenfrom C₁-C₄ lower alkanols, polyols and polyol ethers, aromatic alcohols,similar products and mixtures thereof.
 9. The composition as claimed inany one of claims 5 to 8, characterized in that it has a pH of between 3and
 12. 10. The composition as claimed in any one of claims 5 to 9,characterized in that it contains at least one additional oxidation basechosen from paraphenylenediamines, bis(phenyl)alkylenediamines,paraminophenols, ortho-aminophenols and heterocyclic bases other thanthe diaminopyrazole of formula (I), and addition salts thereof with anacid.
 11. The composition as claimed in claim 10, characterized in thatthe additional oxidation base(s) represent(s) from 0.0005% to 12% byweight relative to the total weight of the dye composition.
 12. Thecomposition as claimed in any one of claims 5 to 11, characterized inthat it contains at least one coupler and/or at least one direct dye.13. The composition as claimed in claim 12, characterized in that thecoupler(s) is (are) chosen from meta-phenylenediamines,meta-aminophenols, metadiphenols, mono- or polyhydroxylated naphthalenederivatives and heterocyclic couplers, and the addition salts thereofwith an acid.
 14. The composition as claimed in either of claims 12 and13, characterized in that the coupler(s) represent(s) from 0.0001% to10% by weight relative to the total weight of the dye composition. 15.The composition as claimed in any one of claims 5 to 14, characterizedin that the addition salts with an acid are chosen from thehydrochlorides, hydrobromides, sulfates, tartrates, lactates andacetates, and the addition salts with a base are chosen from thoseobtained with sodium hydroxide, potassium hydroxide, ammonia or amines.16. A process for dyeing keratin fibers, and in particular human keratinfibers such as the hair, characterized in that at least one dyecomposition as defined in any one of claims 5 to 16 is applied to thesefibers, for a time that is sufficient to develop the desired coloration,either in air or using an oxidizing agent, optionally in the presence ofoxidation catalysts.
 17. The process as claimed in claim 16,characterized in that the coloration is revealed solely on contact withatmospheric oxygen.
 18. The process as claimed in claim 16,characterized in that the color is revealed at acidic, neutral oralkaline pH with the aid of an oxidizing agent, which is added to thedye composition just at the time of use, or which is present in anoxidizing composition applied simultaneously or sequentially in aseparate manner.
 19. The process as claimed in claim 16 or 18,characterized in that the oxidizing agent is chosen from hydrogenperoxide, urea peroxide, alkali metal bromates and persalts such asperborates and persulfates.
 20. A multi-compartment device ormulti-compartment dyeing “kit”, a first compartment of which contains adye composition as defined in any one of claims 5 to 15, and a secondcompartment of which contains an oxidizing composition.